<div dir="auto"><div class="gmail_quote gmail_quote_container" dir="auto"><div dir="ltr" class="gmail_attr">On Tue, Nov 3, 2026, 7:33 PM BillK via extropy-chat <<a href="mailto:extropy-chat@lists.extropy.org">extropy-chat@lists.extropy.org</a>> wrote:</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_quote"><div style="font-family:arial,sans-serif;font-size:small;color:rgb(0,0,0)" class="gmail_default"></div><div style="font-family:arial,sans-serif;font-size:small;color:rgb(0,0,0)" class="gmail_default">I gave your comment to Qwen AI and asked for an explanation.</div><div style="font-family:arial,sans-serif;font-size:small;color:rgb(0,0,0)" class="gmail_default">The answer was complicated, as time travel usually gets weird!</div></div></div></blockquote></div><div dir="auto"><br></div><div dir="auto">And that analysis missed the objection.</div><div dir="auto"><br></div><div class="gmail_quote gmail_quote_container" dir="auto"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_quote"><div style="font-family:arial,sans-serif;font-size:small;color:rgb(0,0,0)" class="gmail_default"><div dir="ltr"><span><span>If a CTC exists, the geometry of the universe allows a continuous, forward-moving path (a timelike curve) that eventually loops back to that exact 4D coordinate.</span></span></div></div></div></div></blockquote></div><div dir="auto"><br></div><div dir="auto">The objection does not discuss returning to the exact same 4D coordinate.</div><div dir="auto"><br></div><div class="gmail_quote gmail_quote_container" dir="auto"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_quote"><div style="font-family:arial,sans-serif;font-size:small;color:rgb(0,0,0)" class="gmail_default"><div></div><h3 dir="ltr"><span><span>4. Correcting the "Beside Yourself" Misconception</span></span></h3><div dir="ltr"><span><span>You mentioned: </span></span><em dir="ltr"><span><span>"You instead wind up at some other spatial coordinate at the exact same time."</span></span></em></div><div></div><div dir="ltr"><span><span>This is where the translation from math to English gets tricky. The null coordinate </span></span><span dir="ltr" style="display:inline-block;overflow-x:visible;max-width:100%"><span><span></span><span aria-hidden="true"><span><span style="height:0.4306em"></span><span>u</span></span></span></span></span><span><span> is not "time" in the traditional sense; it is a mixture of space and time (a light wave). </span></span></div><div></div><div dir="ltr"><span><span>If you travel on a path where </span></span><span dir="ltr" style="display:inline-block;overflow-x:visible;max-width:100%"><span><span></span><span aria-hidden="true"><span><span style="height:0.4306em"></span><span>u</span></span></span></span></span><span><span> increases, but you somehow magically managed to return to your starting spatial coordinates (</span></span><span dir="ltr" style="display:inline-block;overflow-x:visible;max-width:100%"><span><span></span><span aria-hidden="true"><span><span style="height:0.625em;vertical-align:-0.1944em"></span><span>x</span><span>,</span><span style="margin-right:0.1667em"></span><span style="margin-right:0.0359em">y</span><span>,</span><span style="margin-right:0.1667em"></span><span style="margin-right:0.044em">z</span></span></span></span></span><span><span>), you would </span></span><strong dir="ltr"><span><span>not</span></span></strong><span><span> be at the "same time." Because your </span></span><span dir="ltr" style="display:inline-block;overflow-x:visible;max-width:100%"><span><span></span><span aria-hidden="true"><span><span style="height:0.4306em"></span><span>u</span></span></span></span></span><span><span> coordinate has increased (say, from 5 to 8), you are now intersecting a completely different light wave. In the geometry of that universe, you have arrived in the </span></span><strong dir="ltr"><span><span>future</span></span></strong><span><span>. </span></span></div><div></div><div dir="ltr"><span><span>To arrive in the </span></span><em dir="ltr"><span><span>past</span></span></em><span><span> (to form a CTC), you would have to travel backward through the light waves (from </span></span><span dir="ltr" style="display:inline-block;overflow-x:visible;max-width:100%"><span><span></span><span aria-hidden="true"><span><span style="height:0.4306em"></span><span>u</span><span style="margin-right:0.2778em"></span><span>=</span><span style="margin-right:0.2778em"></span></span><span><span style="height:0.6444em"></span><span>8</span></span></span></span></span><span><span> back down to </span></span><span dir="ltr" style="display:inline-block;overflow-x:visible;max-width:100%"><span><span></span><span aria-hidden="true"><span><span style="height:0.4306em"></span><span>u</span><span style="margin-right:0.2778em"></span><span>=</span><span style="margin-right:0.2778em"></span></span><span><span style="height:0.6444em"></span><span>5</span></span></span></span></span><span><span>). But the "three lines of math" prove that the geometry of the universe physically forbids a massive object from moving backward through a light wave.</span></span></div></div></div></div></blockquote></div><div dir="auto"><br></div><div dir="auto">The form of time travel in the objection is not returning to the same (u,x,y,z).  It is returning to the same u at some other (x,y,z).</div><div class="gmail_quote gmail_quote_container" dir="auto"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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